Draft cut-off for steam-engines



(No Model.) A. M. ZIMMERMAN.

DRAFT GUT-OFF FOR STEAM ENGINES.

No. 394,430. Patented Dec. 11, 1888.

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UNITED STATES PATENT OFFICE.

ABRAHAM M. ZIMMERMAN, OF MARTINSDALE, PENNSYLX'ANIA.

DRAFT CUT-OFF FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 394,430, dated December 11 1888.

Application filed August 8, 1888. Serial No. 282,241. (No model.)

To all whom it may concern:

Be it known that I, ABRAHAM M. ZIMMER- MAN, a citizen of the United States, residing in Martinsdale, in the county of Lancaster and State of Pennsylvania, have iiwented certain Improvements in Draft Cut Offs for Steam-Engines, of which the following is a specification.

My invention relates to that class of devices by which thedraft caused by the escape of the exhauststeam into the stack is out 01f; and my object is, when desirable, to carry oif the exhaust-steam through the stack, and at the same time prevent it from acting upon the draft through the fire-chamber. This cut-off of the draft caused by the exhaust is intended more particularly to be applied when the door of the fire-chamber is opened to throw in fuel and prevent the rush of cold air through the chamber which takes place when the exhaust is acting upon the draft.

My invention consists in the combination of a pipe having one end pivoted in the top of the stack and the other connected with a rod, by which it is either held over the end of the exhaust-pipe in the bottom of the stack, or against the side thereof away from the exhaust-pipe, and connections between said rod and the door of the fire-chamber, so arranged that the opening of that door will connect the lower end of the pivoted pipe with the exhaust-pipe, and the closing of the door disconnect it.

In the drawings accompanying this specification, Fignre 1 is a side elevation of a boiler and stack with my invention attached thereto, the stack being shown in section. Fig. 2 is an end elevation, and Fig. 3 a top or plan view of the same. Figs. 4and 5 show a front and top view, respectively, of the arm cl; and

.Figs. 6 and 7, a top and side view of the link r.

A represents the boiler; B, the smoke-stack C, the exhaust-pipe; D, the fire-box, and E the door leading into the fire-chamber.

F represents the cut-off pipe, having the upper end pivoted between the jaws a at the top of the stack. A rod, G, engages the lower end of the pipe F, and extends backward through a perforation in the stack beyond the rear end of the boiler. It is supported over the fire-box by a standard, I), and is encircled by a spring, 0, that bears against the standard and a boss, g, on the rod G. By moving the rod (Jr forward it pushes the lower end of the pipe F over the exhaust-pipe, while the removal of the pressure upon it permits the spring to retract the rod and disconnect the pipe F from the exhaust-pipe.

()n the door E is secured an arm, (I, which is connected with the crank it of the vertical rod H by a link, 1'. This link is provided with a slot, c, that engages the vertical part f of the crank h, to overcome the difference in the length of the movement of the arm (I of the door and the lower end of the cut-off pipe, and also permits the movement of the rod (1 by hand without affecting the position of the door. Brackets I support the rod II in a vertical position, holding it a sufficient distance from the face of the boiler and fire-box to permit the crank 72 to move freely behind the rod. A crank, m, on the upper end of the rod H engages the eye a in the rod G. As can be seen by the drawings, the link r and rod G are removably connected with the rod II. The opening of the door E rotates the rod II, as shown by the arrow in Fig. 3, thus acting through the crank in and rod G, throwing the pipe F into engagement with the exhaustpipe C, while the closing of the door disconnects the same.

The rod G can be moved directly by hand by disconnecting it from the crank m.

The engagement of the cut-off pipe with the exhaust-pipe, caused by opening the door of the fire-chamber, carries the steam through the stack without in any way affecting the draft through the fire-chamber, thereby preventing, to a great extent, the inrush of air when the door is opened to fire up, that is so injurious to the pipes of the boiler. Closing the door again permits the free escape of steam into the stack.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an engine, the combination, with the stack and exhaust-pipe, of a cut-off pipe having one end pivoted or hinged in the top of the stack, and the other free to be moved over the exhaust-pipe or disconnected therefrom, and an attachment for moving said door opening into the fire-chamber, the stack, and the exhaust-pipe, of a device for cutting off the escape of steam from the exhaust-pipe into the stack, and connections between the said door and device, whereby the action of the cut-off device may be regulated by the movements of the door, for the purpose specified.

ABRAHAM M. ZIMMERMAN.

WVitn esses:

I. C. ARNOLD, \VM. R. GERHART. 

